Electronic combination lock system



United States Patent 3,411,046 ELECTRONIC COMBINATION LOCK SYSTEM John M. Swannick, Dover, N.J., assignor to the United States of America as represented by the Secretary of the Army Filed June 6, 1966, Ser. No. 556,812 Claims. (Cl. 317-134) The present invention relates to lock systems for safes, filing cabinets, security rooms and like enclosures, and more particularly to an electronic combination lock system therefor.

Locking means for such enclosures normally involve movable closure elements providing access to the interior thereof, such as doors and other cover elements with movable mechanical locking means. Presently mechanical devices, such as keys and dials, are used to operate various types of mechanical locking means. However, these provide less than full security because of the fact that they can be opened by trial and error methods generally. Furthermore, such mechanical devices are generally more complex and costly to make since they require exacting manufacturing procedures.

Electronic lock systems, however, may be made to provide reliable, simple, inexpensive, and secure locking means for enclosures of the type referred to, and to deny unauthorized access thereto which has long been recognized as a major problem.

It is therefore a primary object of this invention to provide an improved electronic combination lock system which is superior to mechanical devices and effectively prevents tampering attempts to unlock an enclosure protected by it.

It is also an object of this invention to provide an improved electronic combination lock system which consists of a minimum of stationary and moving parts and in which code processing elements as used may be completely of the solid-state electronic type which do not require exacting fabrication methods or stringent inspection techniques.

It is still a further object of this invention to provide an improved electronic combination lock systemof the type referred to, wherein mechanical type control devices are eliminated and superseded by electronic control means for obtaining the combination to release the lock, that is, the mechanical locking means or closure element referred to.

It is also a further object of this invention to provide an improved electronic combination lock system of the type referred to, wherein a separate electric key unit may be used to effect locking or unlocking operations, and which is detachable to provide a further safety feature for security.

In accordance with the invention, the mechanical locking means referred to is electro-mechanically actuated, as by a solenoid, under control of suitable relay means responding to a control circuit of the solid state type, preferably of the AND gate type. The output gate is controlled by suitable flip-flop switching circuits which respond to control signals from the key element through a coder in the connection circuit for establishing the proper sequence of signals to be applied thereto from a second set of flip-flop circuits. Each is under control of the key circuit or unit which may be attached to and detached from the remainder of the system, the lock unit, as above referred to.

The key unit or circuit includes a selector switch, preferably of the three-position type, providing RESET positions 1 and 2 and a SET position as will be described. Effectively the electronic system provides for obtaining the combination to release the locking means. The system ice employs an electronic key unit which is of the detachable, plug-in type and also provides power for the respective circuits for operating the electronic locking means. This preferably involves a lock unit including transistorized flip-flop circuits and a plurality of control circuits in the form of electronic gates. The invention will further be understood from the following description when considered with reference to the accompanying drawings, and its scope is pointed out in the appended claims.

In the drawing, the single figure is a schematic block diagram of an electronic combination lock system embodying the invention, and referring thereto, the mechanical locking means 5 may be any suitable movable mechanical element or elements for locking the closure means for the area to be protected such as the safe door, the file drawers of a file cabinet or a cover element of a security container or a room door, for example. Generally such locking means take the form of movable bolts which move into engagement with the closure element to hold it firmly in place against all mechanical efforts to remove it. In accordance with the present invention this locking means is moved by electro-mechanical means such as an electric motor or preferably a more simplified motor means such as a solenoid as indicated at 6 and con nected with the mechanical locking elements by mechanically movable means indicated at 7.

The solenoid or electro-mechanical operating means 6 is controlled in turn by a suitable silicon-controlled switch 8 and a control switch 9 therefor. The switch 9 may be a similar silicon-controlled device, also as indicated by the two block elements shown.

The switch 9 is actuated by the main control element of the circuit which is an AND gate 2 connected with the switch 9 through a lead or control connection 3 and system ground 4, which is shown generally throughout the figure as the common return circuit of the system. The input circuits 10 and 10A of gate 2 are connected respectively with the high or ONE and low or ZERO output-terminals of the two final flip-flop circuits 16 and 17 respectively. The flip-flop circuits are provided with SET and RESET control circuits indicated by the circuit leads 18 and 19 for the flip-flop 16 and the circuits 20 and 21 for the flip-flop 17. The circuits 19 and 21 are connected respectively with a coincidence Gate 1 and an OR Gate 22. The return connection for these circuits is through system ground 4 as herebefore referred to.

The coincidence Gate 1 and OR Gate 22 are each provided with a plurality of input circuits leads indicated at 24 and 25 which are connected through a code container of inner connector 26 with the high and low or ONE and ZERO output leads 27 and 28 of a series of flip-flop circuits 11, 12, 13, 14 and 15, with system ground providing the return connections therefor. The flip-flop circuits 11-15 are provided with SET and RESET circuit connections 29 and 30 respectively with corresponding terminals or contact elements 31 in a lock connector block 32. This is the lock element of the system and pro vides the terminal end of the circuitry contained Within the Lock or Lock Unit 33.

The remainder and detachable portion of the system is contained within a Key Unit 35 having a key connector or terminal block 36 for the circuitry therein. The connector or block 36 is also provided with terminals 37-48 inclusive corresponding to the terminals 31 in the lock connector block 32 and adapted to be engaged therewith when the key connector 36 is connected with the Lock Unit 33 through the lock connector block 32.

In the Lock Unit 33, the leads 29 and 30 for the flipflop circuits 11-15 inclusive are connected respectively with the SET and RESET terminals as indicated thereon. In the lock connector block 32 the terminals 47A and 3 48A are provided for the leads 19 and 20 from the flipflop circuits 16 and 17 to engage the corresponding ter minals 47 and 48 in the key connector block 36.

The electronic Key Unit provides the power supply and the correct inner connector circuitry for controlling the opening of the electronic Lock Unit 33 when the lock connector 32 and the Key connector 36 are interconnected. The three-position switch 50 in the key unit is provided by a movable switch or contact arm 51 which normally engages the switch contact 52 for the RESET 1 position. Additional active contacts for the arm 51 are provided as indicated at 53 and 54 for the RESET 2 and the SET positions, and a blank contact 55 is provided for the off position. The contact arm 51 is connected to system ground through a common connection lead 56 while the contact 52 is connected through a lead 57 with an inter-connecting bus bar 58. A second bus bar 59 is connected through a lead 60 with the switch contact 54. The remaining contact 53 of the switch is connected jointly through two leads 61 with the terminals 47 and 48 of the Key connection block 36 and, when in engagement with the lock connector block 32 provide connections with the leads 19 and 20 and the RESET terminals of the flip-flop circuits 16 and 17. The bus bars 58 and 59 are located in positions parallel to one another and provide any desired cross-over switching connections, such as indicated, with the leads from the terminals 37-48 inclusive of the key connector 36. With this grid structure different ones of the terminals 37-46 may be connected with either one or the other of the bus bars 58 or 59 to establish a predetermined locking sequence for the lock system. In the present example the terminals 37, 40, 41, 43 and 46 are connected with the bus bar 59 while the terminals 38, 39, 42, 44 and 45 are connected with the bus bar 58. This establishes a SET and RESET group of connections for the flip-flop circuits 11-1'5 whereby on position of contact 52 they are RESET and on the contact 54 they are SET. On the terminal 53 for RESET 2 the leads 19 and 20 are energized to RESET both of the flip-flop circuits 16 and 17.

Energy for operation of the different circuits is provided by battery means in the key unit in the present example, although they may be external thereof. This consists of three battery units 63, 64 and 65 connected to the ground lead 56 and to supply terminals 66 in the key connector 36. These terminals are adapted for engagement with similar terminals or contacts 67 in lock connector 32 for the supply circuits of the Lock Unit 33.

In the code container or inter-connection unit 26, the various circuit leads 27 and 28 may be cross connected with any of the circuit leads 24 and 25 for the coincidence and OR gates, for example, as indicated in the dotted lines, utilizing a grid system similar to that of the key unit for cross connection as desired.

The three position switch 50 in the electronic key is normally in the RESET 1 position and resets each flip-flop circuit in the lock unit by applying input voltage to either the SET or RESET terminals as determined by the interconnections within the key unit previously described. In the present example all of the flip-flop circuits are reset except for the circuits 16 and 17. The OR gate 22 is closed and the flip-flop circuit 17 is set. Therefore the gate 2 is inhibited. When the switch 50 is turned to the RESET 2 position the flip-flop circuit 17 is reset and the Gate 2 is then added.

When the switch 50 is turned to the SET position at the terminal 54, the correct code is then read into the lock unit by setting the flip-flop circuits 11-15 in accordance with the predetermined connections made in the Key Unit 35. The high or ONE output terminals from the flip-flop units 11-15 is applied to the coincidence Gate by way of the code container or connector 26. In the present example, the coincidence Gate 1 is then closed and thus the flip-flop circuit 16 is set. As the high or ONE side of the flip-flop circuit 16 is applied to the Gate 2, this gate is closed. The signal output which comes from the Gate 2 is used to trigger the Silicon Control Switch 9 which, in turn, is used to fire the Silicon Controlled Rectifier or switch 8. The output functional device 6 is thus operated, and the electronic locking device or mechanical locking means is opened.

If the wrong code is used or if the electronic locking device is tampered with, at least one of the flip-flop circuits 11-15 will not SET properly, in which case the high or ONE state from all of the code flip-flop circuits will not appear at the coincidence Gate 1 and the gate will not close. Therefore, the high or ONE output of at least one of these flip-flop circuits will trigger the OR gate 22, thus setting the flip-flop circuit 17 and hence inhibiting the output Gate 2. The electronic locking system or unit will not open or cannot open even with the correct code key. However, by using improper sequence the RESET 1, RESET 2, and SET positions of the control switch 50, and the correct code, the device can be opened again. Code changes are effected by replacing the code container or by changing the connections in a single container, although the selection is expedited if the code container is prewired and adapted to plug into the circuit.

Contributing factors to the systems security are due to the fact that power may be applied from an external source to the electronic locking device or Key Unit 35 without changing its function. Also the proper sequence of events RESET 1, RESET 2 and SET are applied to the proper input terminals by the selector switch 50. Unless operated in that order the system does not properly function and, when operated, the key is then removed so that tampering is practically impossible. Furthermore, the correct and complete code is read into the lock unit simultaneously by the operation of the selector switch. And finally the locking system is disabled by the first unsuccessful attempt to open or unlock, as when the wrong code is applied or the sequence is applied in the wrong direction or out of order.

Because of its unitary construction, both the Lock Unit and the Key Unit may include printed circuitry, while the connectors and switches are preassembled for a high degree of accuracy and cost reduction in manufacture. Furthermore, the apparatus may be designed to operate on any suitable direct current supply, voltage either positive or negative with respect to the reference ground, and with little or no change in the electronic locking device or unit 33.

From the foregoing description it will be seen that an electronic combination locking system in accordance with the invention comprises two separable units comprising a Lock Unit and a Key Unit adapted to be connected by connector blocks which elfectively provide a lock and key relation for operation of the system. When the key is withdrawn the system is safe and may not be changed, and when the key is connected the right code must be established in order to operate the switch and gate means as set up through the code container and the key unit.

I claim:

1. An electronic combination lock system comprising in combination, mechanical locking means operable to move between locked and unlocked position, electromechanical means connected for operating said locking means, an electronic switch and switching means therefor connected to energize and control said operating means, an electronic gate connected to control said switching means and having high and low input circuits, a pair of flip-flop circuits connected each with one of said input circuits to apply operating. current thereto, said flip-flop circuits each having a Set and a Reset input terminal, an electronic coincidence gate connected to apply operating current to the Set input terminal of one of said flip-flop circuits, an OR gate connected to apply operating current to the Set input terminal of the other said flip-flop circuits, each of said Coincidence and OR gates having a plurality of input circuit leads, a series of flip-flop control circuits equal in number to the number of input circuit leads of said Coincidence and OR gates, each of said flip-flop control circuits having high and low output leads, means for selectively interconnecting said high and low input leads and the input leads of said Coincidence and OR gates comprising a code container adapted to establish a predetermined coded circuit relation and operating sequence for said gates, the aforesaid circuit elements and circuit connecting means providing a lock unit for said system and lock connector terminal means for the circuitry thereof including control connections for said flip-flop circuits for Set and Reset conditions, a detachable key unit for said system having key connector providing terminal means for engaging the lock connector terminal means to provide power and control therewith, means in said key unit for establishing a predetermined circuit relation between said terminals and supply circuits therefor, a selector switch for controlling said supply circuits and including first and second Reset positions and a Set position for sequencial adjustment in operation to apply control signals to said main gate through said Coincidence .and OR gates, and to effect locking and unlocking operation of said mechanical locking means.

2. An electronic combination lock system for a mechanically movable locking means comprising in combination, an electronic lock unit for operating said locking means and including an electro-mechanical operating device therefor, and an electronic key unit, said lock and key units each having a lock and key connector providing terminals adapted to be engaged in operation and to be disconnected out of operation, and said lock unit further including a plurality of flip-flop circuits adapted to control said electro-mechanical operating elements selectively in accordance with established connections to set and reset the circuit elements of said lock unit.

3. An electronic combination locking system as defined in claim 2 wherein the electro-mechanical control element is connected with said flip-flop control circuit through a control gate responsive to signals therefrom under control of a pair of gate circuits of the Coincidence and OR type and wherein a code container is provided for establishing circuit connections between flip-flop circuits and said gate further to establish a predetermined switching sequence in response to operation of said switch in said key unit.

4. An electronic combination locking system comprising in combination, separable key and lock elements providing a plurality of terminals in a pair of engaging terminal blocks, control circuits in said lock unit and control circuits in said key unit for establishing a predetermined sequence of operation in said system, the control circuits in the lock unit including a plurality of flip-flop circuits and an output gate circuit controlled thereby in response to operation of said key unit, and said key unit further including energizing and control means for said system.

5. An electronic combination lock system comprising in combination, a lock unit and a key unit of the plug-in type detachably-connected therewith elfectively in a lock and key relation, said lock unit including mechanical locking means, electro-mechanical means for operating said locking means, electronic-gate-controlled electronic-relay and switch means connected to control said operating means, a pair of flip-flop circuits connected to apply high and low output signals to said last named means to control the gating thereof, a Coincidence electronic gate and an OR electronic gate connected to set the one and the other of said flip-flop circuits individually, said last named gates each having a plurality of input connections and a corresponding number of operating flip-flop circuits with low and high output circuits connected with the said input connections for said gates according to a changeable coded operating sequence, and a code container network for effecting different cross-connections between said Coincidence and OR gates and said last named operating flip-flop circuits to change said coded operating sequence, and said key unit having selector switch means and circuit connections for applying operating signals to set and reset said operating flip-flop circuits selectivity in different combinations and to reset said firstnamed pair of flip-flop circuits.

References Cited UNITED STATES PATENTS 3,093,994 6/1963 Richard. 3,347,072 10/1967 Rose 277 3,320,490 5/1967 Beck et a1. 317-134 LEE T. HIX, Primary Examiner.

W. H. BEHA, JR., Assistant Examiner. 

2. AN ELECTRONIC COMBINATION LOCK SYSTEM FOR A MECHANICALLY MOVABLE LOCKING MEANS COMPRISING IN COMBINATION, AN ELECTRONIC LOCK UNIT FOR OPERATING SAID LOCKING MEANS AND INCLUDING AN ELECTRO-MECHANICAL OPERATING DEVICE THEREFOR, AND AN ELECTRONIC KEY UNIT, SAID LOCK AND KEY UNITS EACH HAVING A LOCK AND KEY CONNECTOR PROVIDING TERMINALS ADAPTED TO BE ENGAGED IN OPERATION AND TO BE DISCONNECTED OUT OF OPERATION, AND SAID LOCK UNIT FURTHER INCLUDING A PLURALITY OF FLIP-FLOP CIRCUITS ADAPTED TO CONTROL SAID ELECTRO-MECHANICAL OPERATING ELEMENTS SELECTIVELY IN ACCORDANCE WITH ESTABLISHED CONNECTIONS TO SET AND RESET THE CIRCUIT ELEMENTS OF SAID LOCK UNIT. 